1[2 {"id":"C1","text":"The OLS Okun coefficient over 1960Q1-2019Q4 (240 quarters) is about -0.256 pp of unemployment change per percent of quarterly real GDP growth, with intercept 0.184 and R^2 0.408.","results_keys":["beta_hat","alpha_hat","r_squared","n_analysed","first_quarter","last_quarter"],"status":"supported","caveat":"Current-vintage data; reduced-form projection, not causal."},3 {"id":"C2","text":"Using a Newey-West Bartlett HAC SE with 4 lags (0.0358), the 95% CI is [-0.326, -0.186]; the coefficient is negative and significantly different from zero at 5%.","results_keys":["se_hac","hac_lags","beta_ci_low","beta_ci_high","okun_negative_5pct","t_stat_hac","p_value_hac"],"status":"supported","caveat":"Asymptotic normal critical value, no small-sample correction."},4 {"id":"C3","text":"The naive iid SE (0.0200) understates uncertainty: residuals have lag-1 autocorrelation 0.39 and the HAC SE is about 1.8 times larger.","results_keys":["se_iid","se_hac","residual_acf_lag1","beta_ci_iid_low","beta_ci_iid_high"],"status":"supported","caveat":""},5 {"id":"C4","text":"The significance conclusion is robust to the HAC bandwidth over 0-12 lags (HAC SE between 0.0288 and 0.0371).","results_keys":["se_hac_by_lags","beta_hat"],"status":"supported","caveat":"Only Bartlett kernel examined."},6 {"id":"C5","text":"Mean quarterly real GDP growth over the sample is 0.754 percent.","results_keys":["mean_growth"],"status":"supported","caveat":""}7]8